2 * New switch: --print-gc-sections to list any sections removed by garabge
7 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
9 * Modify the Linux linker search order to better match ld.so search order.
10 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
11 searching the default directories, rather than vice versa.
12 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
14 * PE-COFF: Forward exports from DLL's can now be specified in .def files
15 passed directly to ld.
17 * Support for the Z80 processor family has been added.
19 * Add support for the "@<file>" syntax to the command line, so that extra
20 switches can be read from <file>.
24 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
25 specification has been added via the --fix-v4bx command-line option.
27 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
28 for input files listed inside of it.
30 * A new command-line option, --sysroot, can be used to override the
31 default sysroot location. It only applies to toolchains that were
32 configured using --with-sysroot.
34 * New linker script functions: ORIGIN() and LENGTH() which return information
35 about a specified memory region.
37 * Port to MAXQ processor contributed by HCL Tech.
39 * Added SEGMENT_START to the linker script language to permit the user to
40 override the base address for a segment from the command-line.
42 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
45 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
46 language to permit sorting sections by section name or section
49 * Added a new linker command line switch, --sort-section name|alignment,
50 to sort sections by section name or maximum alignment.
52 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
53 should be added when a shared library comes from DT_NEEDED tags.
55 * Support for the crx-elf target added.
57 * Support for the sh-symbianelf target added.
59 * A new linker command line switch has been added which allows the hash table
60 size to be set to a suitable prime value near to its argument. This switch
61 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
62 used, and --hash-size has not been used, then the default value will be set
65 * Linker map files are now generated with an O(N) algorithm for finding symbols
66 that are defined in each section. This uses about 40% more memory for
67 symbols than the old O(N^2) algorithm. You can use the new
68 --reduce-memory-overheads option to select the old algorithm; this option
69 might also be used in the future to select similar tradeoffs.
73 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
74 be added only when a shared library is referenced.
76 * PE: --large-address-aware option to indicate executables support virtual
77 addresses greater than 2 gigabytes.
79 * DWARF 2 support for i386pe added.
81 * The linker script operator DEFINED() will now yield 1 only for a symbol that
82 is defined before the statement where DEFINED is used.
84 * The MIPS --embedded-relocs (used to embed relocations into binaries for
85 Embedded-PIC code) is deprecated and will be removed in a future release.
87 * cr16c support added by NSC.
89 * m32r Linux (ELF) support added by Renesas.
91 * Improved linker's handling of unresolved symbols. The switch
92 --unresolved-symbols=<method> has been added to tell the linker when it
93 should report them and the switch --warn-unresolved-symbols has been added to
94 make reports be issued as warning messages rather than errors.
98 * Added support for Xtensa architecture.
100 * Added --with-sysroot configure switch to specify a target system root, for
101 linking against a target filesystem image.
103 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
104 2.14) of silently accepting and linking in any files in an unknown binary
107 * Added --no-omagic to undo the effects of the -N option.
109 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
110 DSP's contributed by Michael Hayes and Svein E. Seldal.
112 * Added --with-lib-path configure switch to specify default value for
115 * ARM port to QNX operating system added by Graeme Peterson.
117 * IP2K support added by Denis Chertykov.
121 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
124 Changes in version 2.13:
126 * DEC VAX ELF support, by Matt Thomas.
128 Changes in version 2.12:
130 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
132 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
134 * Support for -z nocopyreloc in the x86 ELF linker, which disables
135 production of copy relocs. Warning: using this option may result in
136 non-sharable applications.
138 * Support for -z combreloc in the ELF linker, which puts dynamic
139 relocations against the same symbol together, so that dynamic linker
140 can use an one-entry symbol lookup cache.
142 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
144 Changes in version 2.11:
146 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
148 * Support added for eliminating duplicate DWARF2 debug information by
149 having the compiler generate the information in sections called
150 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
151 linker then merges these sections together into the normal .debug_info
154 * The native ELF linker now searches the directories in DT_RUNPATH or
155 DT_RPATH of a shared library for shared libraries needed by it.
157 * TI C54x support, by Timothy Wall.
159 * Added command line switch --section-start to set the start address of any
162 * Added ability to emit full relocation information in linked executables,
163 enabled by --emit-relocs. Some post-linkage optimization tools need
164 this information in order to be able to correctly identify and perform
165 symbol relative addressing in the event of changes in section contents
166 (instructions being added or deleted, extending data sections, etc.)
168 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
170 * Support for CRIS (Axis Communications ETRAX series).
172 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
174 Changes in version 2.10:
176 * Added AT> to the linker script language to allow load-time allocation of
177 sections into regions.
179 * Added garbage collection of unused sections, enabled by --gc-sections.
180 It does require a bit of backend support; currently implemented are
181 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
182 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
183 Others will ignore the option.
185 * Added SORT to the linker script language to permit sorting sections by file
186 name or section name.
188 * Added EXTERN to the linker script language as an equivalent to the -u
191 * Added ASSERT to the linker script language.
193 * Added EXCLUDE_FILE to the linker script language for further control over
196 * Added -O option to optimize linker output (as of this writing, this only
197 affects ELF shared library generation).
199 * The -e option now accepts a number as well as a symbol name.
201 * Added --no-undefined option to disallow undefined symbols when creating a
204 * The linker now issues a warning, not an error, for an undefined symbol when
205 using -Bsymbolic; use the new --no-undefined option to get the old
208 * Added --demangle and --no-demangle options.
210 Changes in version 2.9:
212 * Added SQUAD to the linker script language.
214 * New option --no-warn-mismatch.
216 * The MEMORY command now parses the attributes to determine where sections that
217 are not placed in a specific memory region are placed.
219 Changes in version 2.8:
221 * Linker scripts may now contain shell wildcard characters for file and section
224 * The linker now supports symbol versions in ELF.
226 * The NOCROSSREFS command was added to the linker script language.
228 * The LOADADDR expression was added to the linker script language.
230 * MAX and MIN functions were added to the linker script language.
232 * The OVERLAY construct was added to the linker script language.
234 * New option --warn-section-align to warn when the address of an output section
235 changes due to alignment of an input section.
237 * New options --filter/-F and --auxiliary/-f.
239 Changes in version 2.7:
241 * New option --cref to print out a cross reference table.
243 * New option --wrap SYMBOL.
245 * New option --no-whole-archive, to turn off the effect of --whole-archive.
247 * Input sections assigned to the output section /DISCARD/ in the linker script
248 are not included in the output file.
250 * The SunOS and ELF linkers now merge stabs debugging information which uses
251 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
252 information generated.
254 Changes in version 2.6:
256 * When an ELF section name is representable as a C identifier (this is not true
257 of most ELF section names), the linker will automatically define symbols
258 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
259 beginning and the end of the section. This is used by glibc.
261 * When an ELF section named .gnu.warning is encountered in an input file, the
262 contents of the section are displayed as an error message, and the section is
263 not copied into the output file. This is used by glibc.
265 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
266 file, and the symbol SYMBOL is referenced by some object file, the contents of
267 the section are displayed as an error message. The section is not copied into
268 the output file, unless doing a relocatable or shared link. This is used by
271 * New options -split-by-reloc and -split-by-file.
273 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
274 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
275 will do so whenever there is an undefined symbol in the link and neither the -e
276 nor the -r option was used.
278 * The -rpath option may be used on SunOS to set the list of directories to be
279 searched at run time. This overrides the default of building the list from the
282 * The COFF linker now combines debugging information for structs, unions, and
283 enums, so that even if the same type is defined in multiple input files it will
284 only be defined once in the output file. The --traditional-format switch will
285 prevent this optimization.
287 Changes in version 2.5:
289 * The linker now supports linking against SunOS shared libraries. It still can
290 not link SunOS PIC (Position Independent Code) files, so it can not be used to
291 generate shared libraries.
293 * The linker now supports linking against ELF shared libraries for the i386
294 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
295 used to generate shared libraries. Shared library generation is not well
296 tested; please report any problems encountered. The linker is now enabled for
299 * Eric Youngdale has contributed Linux support code, including linking against
300 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
302 * The ELF backend has been converted to the new linker code. To use the new
303 ELF linker, each particular target requires a relocation function. So far,
304 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
305 5), and HPPA ELF targets.
307 * The -( (--start-group) and -) (--end-group) options have been added to
308 support searching a group of archives as though they were a single archive.
309 This can also be used in a linker script, as GROUP ( files ).
311 * When a file is named on the command line, and the linker does not recognize
312 it as an object file, the linker will now treat the file as a linker script
313 file. A linker script named in this way augments, but does not replace, the
314 default linker script.
316 * The -warn-once option was added. It causes the linker to only warn once per
317 undefined symbol, rather than once per reference.
319 * The COFF backend has been converted to the new linker code. As with ELF, to
320 use the new linker, each particular target requires a relocation function. So
321 far, this function has been written for the i386, m68k, a29k and SH targets.
323 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
324 behaviour is available via --verbose.
326 Changes in version 2.4:
328 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
329 formats (so far), this should result in considerable savings in time
330 and memory used while linking; slightly poorer performance than
331 before for formats not converted yet.
333 * Command-line parsing is no longer done with flex. This means
334 oddball characters in filenames won't get treated as argument
337 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
339 * Mach i386 support, by David Mackenzie.
341 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
342 libraries are not yet supported).
344 * COFF shared libraries (as on SCO) should work as well.
346 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
347 forgot to note it.) Some of their C library routines don't work when
348 statically linked, and the GNU linker doesn't support dynamic linking yet.
350 Changes in version 2.3:
352 * Weak symbols are now supported.
354 * ELF support has been added. The linker has been bootstrapped on
355 UnixWare and Solaris.
357 * Alpha OSF/1 support has been added (non dynamic linking only).
359 Changes in version 2.2:
361 * The `bfd' library has been updated to reduce a.out-format string
362 table size. The effect of this is that files linked from many input
363 files with duplicate symbols (`-g' debugging records, or identical
364 static symbols) should be much smaller.
366 Changes in version 2.1:
368 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
370 * There is now support for writing ECOFF files, so ld and the
371 other utilities should work on Risc/Ultrix and Irix.